Should You Convert Your Photos To DNG?

Upload from June 12, 2012

 

The world of digital photography changes FAST. It’s a fun and exciting time, with new gadgets coming out all the time. But as a digital shooter you need to think ahead to the future, and figure out how you can protect your images from the changing times!

If you’re not planning right, you might end up with an archive of images that you can’t even open. Uh oh. Read on to learn more about this subject, and how you can prevent that from happening to you!

Now, if you shoot in the RAW file format you may or may not have heard of the Digital Negative (DNG) format. The DNG is an open source RAW file format that was developed by Adobe and released in 2004. You might want to consider converting your RAW files to the DNG format as it offers some serious benefits!

The Benefits Of DNG

Future Compatibility

One of the problems in photography right now is that the vast majority of camera manufacturers have their own proprietary RAW formats. If you shoot Canon you might have noticed your RAW files end with .cr2, or with Nikon it’s .nef. These proprietary formats might be difficult to read in the distant future since the format hasn’t been openly documented and support from the manufacturer may not always be there. It’s hard to imagine not being able to open Canon or Nikon files today, but ten or twenty years from now who knows where those companies could be!

Since the DNG format (.dng) is open source anyone can write software to read or write the format. It’s not limited to Adobe software like Lightroom and Photoshop. Many different software developers support the DNG format (Apple Aperture for example).

There are also no license restrictions so camera manufacturers could use DNG as their default RAW format instead of their proprietary format. Some camera manufacturers like Leica and Hasselblad already capture in the DNG format. If (when) other camera manufacturers adopt a universal format in the future it’s highly likely it will be the DNG.

Smaller File Size

DNG files are around 15-20% smaller in file size than proprietary RAW files without any loss of quality! You also have the option to include the original proprietary RAW file in the DNG which effectively doubles the file size – though it’s not really necessary.

No XMP sidecar files

XMPs are metadata files that can exist next to the original RAW file (.xmp). They basically contain instructions about how the file should be processed. For example, if you’re using a program like Lightroom to edit your images, changes to adjustments like exposure and temperature could be stored in the XMP file. Because the XMP data is a separate file it can be an organizational challenge keeping the original RAW file and the XMP file together. It’s just messier having two files! With the DNG format the XMP data is included in the DNG file, so you don’t have to worry about the XMP data getting separated from the original DNG. Makes it quite a bit simpler to keep things organized!

Embedded file verification

The DNG format includes a checksum that can detect file corruption. With regular RAW files it can be impossible to detect file corruption. This is a pretty important archival feature for an image format to have.

Where You Can Convert To DNG

Using Lightroom you can convert to DNG right on import. Or you can select “Convert Photos to DNG…” from the Library Menu in the Library Module (see the image above). I would suggest converting to DNG after import as the conversion process does take a bit of time and seriously slows down import!

You can also use a stand alone DNG conversion tool.

Should You Convert JPEGs To DNG?

It is possible to convert JPEGs to DNG but it might not be necessary. JPEG is already a standard image format that will be compatible far into the future. By converting to DNG you do gain most of the benefits listed above but you also increase the file size a bit.

One big advantage is that by converting JPEGs to DNG you gain the non-destructive characteristic of RAW and DNG files. That means you can’t accidentally make adjustments that change the original file (the way you can with JPEGs). In my opinion the biggest reason not to convert JPEGs to DNG is that the JPEG format is already compressed and missing a ton of the original image data. It makes a lot more sense to capture in RAW and convert to DNG than to capture in JPEG and convert to DNG.

Our Approach

We shoot in the RAW format (Canon .cr2, Sony .arw). For our portrait sessions we convert all the selects to DNG for archival purposes (just the selects, not all the images captured during the session since it does take a bit of time to do the conversion). Converting selects might be something you want to consider if you’re a wedding or portrait photographer. For personal work we convert everything to DNG usually on import (if we’re importing a lot of images we’ll save conversaion for later). I’ve also been slowly and steadily converting previously captured images in our archive.

Our adoption of a DNG workflow has happened only recently, in the last year and half (since we started shooting with the Sony NEX). Shooting more personal work has made me think about the future of our image archive and best practices to ensure we can easily access our images 50 years from now!

Side Note: We don’t include the original RAW files when we convert to DNG and I haven’t run into any issues because of it. The only reason I’ve read about to include the original RAW file is if you’re converting to an earlier version of the DNG format where compat
ibility might be an issue – though I haven’t seen any problems reported. So far working with DNGs has been just as easy as working with proprietary RAW files. There’s no real difference in how you edit the files or the quality of the photos.

Do you convert your images to DNG? If not what’s holding you back? Let us know in the comments!

More About DNG

Are you interested in learning how to edit your photos in Lightroom 4? Then check out our Super Photo Editing Skills tutorial below.

Upload from June 06, 2012

Rob Lim

Hi there, I’m Rob! I’m a photography ninja here at Photography Concentrate. I love all things photography: shooting, teaching and always learning more! If I’m not reading up on the latest photography news, or studying a technique, I’m probably reading a book or planning our next adventure!

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Super Photo Editing Skills

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Comments

67 Comments // Leave a comment

  1. Good article, I have just begun switching over to DNG from Canon Raw files, and usually do it on import to make the process simpler. For me it seems to take the same amount of time as a regular import.

    There are some neat new DNG features built into Lightroom 4, including Fast Load Data which helps your image previews come up quicker, which is reason enough to start using DNG. Check out this link for more info http://lightroomsecrets.com/2012/03/lightroom-4-tip-new-dng-options/

  2. DNG is a sloppy standard. Moving from Lightroom to Aperture is far from garanteed (or is it the opposite) and if you keep the data you loose the edits (which would be the case with cr2 or nef anyways).

    It is not supported by most other raw editors and you can't convert back to raw (unless you embed the raw – resulting in a huge file!). So you would be locked into Lightroom of Photoshop by using DNG.

    Lastly, in certain case, the ultimate image quality will be possible with the manufacturers software. For example DPP (from Canon) has lens/camera correction features not available otherwise.

    Use DNG if you wish, but please, keep your original raw somewhere!

    • Hi Jeff,

      I hope you’re still around checking this site.
      2 QUESTIONS:
      Thank you for posting. Are there any other way to save your RAW files
      and where do you save your RAW files? This is the first for me. I shoot
      in RAW and JPEG, but I haven’t fool around with RAW until now. I finally
      was able to open in Adobe PS Elements 10. I started saving the RAW files
      to my external without embedding the original RAW file. Am I doing this
      right or are there smarter steps to take?

      Best Regards,
      jahmenj
      [email protected]

    • You just said “It is not supported by most other raw editors and you can’t convert back to raw (unless you embed the raw – resulting in a huge file!)”. Could you tell me how to convert the DNG files back to RAW?

  3. Hey Jeff!

    Thanks for taking the time to comment and share your thoughts!

    Good points about moving between Lightroom and Aperture. It would be nice if the adjustments made in either program were universal. But as you mentioned the same problem exists with .cr2, .nef, and other proprietary RAW files. Perhaps further adoption of DNG by camera makers and software developers would spur development of an interoperable DNG standard.

    Also a good point about not being able to convert back to the original raw format (unless you embed the original file). Though I'm not sure what you mean by most other raw editors not supporting DNG. Some of the most common raw editors (Lightroom, Aperture, Capture One, DxO, AfterShot Pro) all support the DNG format. So even though you can't convert back to the original raw file your choice of editors is pretty large. Of course it would be an issue if you wanted to use the camera manufacturer's software.

    Unfortunately I haven't tried Canon's Digital Photo Professional in quite a while so I can't comment on the lens / camera correction features for that program. However, the Lens Corrections panel available in Lightroom has been pretty good so far.

    Converting to DNG and replacing the original raw file was initially a tough decision to make. It is scary not being able to go back to the original raw. But for our workflow (using Lightroom) and the future security of our image archive I feel it's been a good decision for us that has been working great.

    • Rob,

      Like you, I’ve gone all-in on the DNG standard (since late 2009) for my workflow and even convert on import with acceptable speed. As with any technology issue, I keep looking back once in a while to see what people are talking about. One of the things I’m finding is that there are layers of “open” and it’s not so clear cut. I tried AfterShot Pro (I’m a former Bibble Pro user) and it supports DNG, but only DNG files captured in certain cameras, NOT the DNGs we’re converting from our Canon or Nikon RAWs. The reason I saw was because something about the file becomes proprietary at that point and the editing software has to know how to handle DNG files created from all of the different RAWs. I don’t know how true that understanding is, but I do know this: I can’t take my DNGs converted from RAW by Lightroom 4 and even browse them in AfterShot Pro, let alone import them. This tells me that by going all DNG in my workflow, I’m betting that 1) ADobe will always be around for me to use my DNG files in their software and 2) I will always want to rely on Adobe products, even if something better comes along.

      My solution: For the best consideration of compatibility, disk space workflow steps, time, etc I’m going to:
      1. Go back to importing as RAW
      2. Be less of a paranoid pack rat and delete the rejects
      3. Convert the final selections to DNG with embedded RAWs (or just keep the RAWs, haven’t decided yet).

      Everything else about my workflow (backup, archiving, etc) will remain, but I think this change will be a better hedge against being stuck with DNGs I might not be able to use later on. I love the DNG format as well, but until it is truly universal, I can’t be all-in like before. I refuse to trust even my favorite software vendor with the idea that they will fully support what they’ve said the format will be. When push comes to shove, if they go out of business or are purchased by someone else I don’t have any guarantees that DNG support will be handled with my best interest in mind. As I re-examine this, I think it is a safer bet that Canon will have my back at this point. I also know that there are tons of editors out there to support my RAWs today, but there appears to be only ONE company to support my DNGs today. I don’t want to accuse Adobe of anything underhanded, but what is their #1 priority? I would say it is to gain as many new users of their product as possible and make it harder to move to someone else’s product. So, creating a “standard” like DNG with the benefits described is clearly an effective way to do just that. I bought into DNG for and openness that does not seem to really be there. I am currently an enthusiastic user of Lightroom and believe it is the best product available today for my needs. Along with having the best product available today, I want the absolute freedom to move to a better product tomorrow. I’ve spent way too much time in the technology world to allow myself to be locked into only one product or technology for the bottom line of my business. I simply can’t afford to make that bet.

      All of that said, none of us can guarantee that Windows, Mac OS or compatibility with the installable copies of our currently licensed software. 25 years ago we had none of this in its current form. Anyone who has spreadsheets from SuperCalc on the CPM OS from 25 years ago (assuming you have them on readable media) might have a challnege in importing that data. I don’t know, I haven’t tried. Probably because the data is irrelevant to me now. The thing that is unique about us in the photography world is that our data is relevant and even sometimes critical to us forever. Sure, maybe not EVERY session we shoot has to be ready for a re-order 25 years from now, but we surely as artists are keeping a portfolio and want some key images to stand the test of time.

      I would encourage everyone to look at the big picture. For most of our sessions, we need to have them around and accessible for 5 to 7 years at best. Maybe RAW isn’t so bad because I have the freedom to at least switch editors without the world changing quite so much. I am still researching this issue and would love to see this dicussion continue. Please correct me on anything I might have stated inaccurately here.

      Doug

      • Hey Doug!

        Thanks so much for commenting and sharing a great perspective! I agree that when you dig down deep into the issue it feels like there are different levels of “open”. I mean DNG is supposed to be an open format, what gives with all this incompatibility?!

        I haven’t used AfterShot Pro so I’m not familiar with how it handles DNGs. I’m surprised that it won’t even open DNGs that were converted from RAW in Lightroom. That’s bizarre. I understand why DNGs that are edited in one program don’t carry over edits to a different program, but it should at least still be possible to open and view the DNG in different programs (eg. DNGs edited in Lightoom won’t show the edits in Apple Aperture but Aperture can still open the DNG file). I figured that this would be the case across all image editors that support DNG.

        While I don’t dig the fact that Adobe is in control of the DNG standard, it is openly documented and freely licensed which means that anyone can develop software to read the DNG files. By converting to DNG I’m definitely making a bet that in the future either Adobe or some other developer will have software that decodes the DNG standard. Hopefully I’ll still be using Lightroom, but in 20 years I’ll settle for any program that can open DNGs.

        A note about camera manufacturers: Kodak is a good company to use as a case study. 20 years ago nobody would have thought a company like that could go bankrupt. Now they’re selling off most of their photographic assets. And I believe the Kodak RAW files .kdc are now widely not supported, you need to track down a converter. In 10-20 years Canon could easily be in a similar situation.

        One last point :) Even if you’re shooting DNG and using Lightroom you still have to deal with process versions being upgraded in the future. Say you processed a DNG in 2010. Well Lightroom has gone and released a new process version (2012) with Lightroom 4. Now you can continue to edit under the old process version (2010), but the new process version (2012) will produce better results. Do you leave all your photos at the old process version, or manually convert each to the newer process version? Now keep in mind this is all within the same editing program, Lightroom. And this is a problem all editing programs will have as processing technology advances. I think this changes the way you should look at editing in the future. In the future when I need to use a photo I’ve taken years ago, I’ll probably re-edit it using the most current processing version. I should point out that this problem will exist no matter whether you’re working with original RAW files or DNGs.

        Thanks again for sharing your thoughts! There’s definitely a lot to think about when trying to secure your image archive for the future. Maybe JPEG is the answer? :P

    • Hi Rob, Very valuable discussion. I am new to raw and DNG. I was hesitating to chose one. I am sceptical to switch to DNG. therefore, did a comparison between Raw and DNG. Suppriselly, after converted the NEF to DNG, no matter use Adobe’ DNG Converter or LR 5.7, the DNG photo seems darkening a little bit and had distortion as well. The later is obvious. I don’t know what cause these. Because of this I decided not switch to DNG but continue using raw.

  4. Hi Rob,

    I stand corrected on Capture One. My understanting is that there are different type of DNG (linear or not) and now even compressed. Dxo only does linear, which is not what Lightroom, Aperture or DNG converter does.

    It is a fact that a single file is much simpler to manage and most certainly counterbalance any other marginal benefits you MIGHT get otherwise. And yes, my total library is probably your weekly output, so my challenges are certainly not yours! I understand how hard the decision must have been!

    Anyways, love the blog. Keep the good work as it keeps our knowledge and perspective current .

  5. I Love DNG, I have been using a DNG workflow for over a year and love the smaller files, I shoot a d800 so any savings are a bonus! Furthermore XMP's are a hassle, I love the simplicity of DNG for my everyday workflow.

  6. This is really helpful! Thank you for doing this post.

  7. Very good post.

    I agreed that DNG is small in size. but if you are converting them just because of the support in future, i really can't convince myself for it. Lets say after 50 years, Nikon Company is gone. No more support for file captured in NEF in year 2012. I am pretty sure, either Nikon or Adobe will provide a tool for you to convert our NEF to DNG before Nikon is gone. Its never too late to convert at that time.

    However, my workflow is already in DNG. Im a event and wedding photographer. I do work with DNG but i will not convert them during import. As you know wedding or events photographer will delete about 10-15% of the photos captured. So there is no point to convert those when you know you are gona delete. I will do my importing and editing in NEF and convert those to DNG in final.

  8. You say that it makes most sense to shoot in Raw and then convert to DNG, not Jpeg to DNG. But, I didn't have my first camera that supported Raw until Dec 2010. I have thousands of photos from before then that are all Jpegs. Should I be converting those to DNG? Is it even worth it to work with Jpegs (even as DNGs), or should I just concentrate my (limited) time on working with the newer Raw files?

  9. Thanks for commenting everyone!

    @ Jack- It's hard to say how proprietary file formats will change. Even if a tool for converting is made available it could be a pretty challenging task converting an archive containing 20, 30, or 50 years worth of proprietary raw files.

    Our workflow is pretty much the same in terms of converting selects to DNG, though we don't delete any of the extra shots.

    @ Alex – You can still work with JPEGs without converting them to DNG. I would say it's still worth working with your JPEGs if they're shots you like.

    When you're working with raw files (original raw files, or raw files that you've converted to DNG) you have more flexibility with the adjustments (because of larger file sizes, more image data).

    When you convert a JPEG to DNG you're still working with the compressed JPEG image data. So you don't gain any increase in image quality by converting JPEGs to DNG.

    So you might have more fun working with your newer raw files since you should be able to produce better quality edits with them.

  10. It was very frustrating to me that Nikon View (admittedly an D200 era) crashed when I tried to import RAW files from a newer camera (D7000). So, if Nikon can't even keep their own NEF files consistent, I doubt if DNG will be either.

  11. I started using DNG after I bought my D7000. I use CS4 and Adobe hasn't (won't) provide the needed upgrades. I can't justify upgrading for this purpose only so I have been using their DNG Converter. It freezes from time to time but what can you do? It has just become part of my workflow and I will likely stay with it even if I upgrade in the future.

  12. I started using DNG after I bought my D7000. I use CS4 and Adobe hasn't (won't) provide the needed upgrades. I can't justify upgrading for this purpose only so I have been using their DNG Converter. It freezes from time to time but what can you do? It has just become part of my workflow and I will likely stay with it even if I upgrade in the future.

  13. One thing I found about converting RAW images to DNG is that the files don’t get smaller if you shot Canon’s sRAW or mRAW sizes. They actually get larger. From what I’ve read, it appears that the sRAW and mRAW formats are compressed and when you convert them to DNG, they get uncompressed.

  14. Let this be a warning – don’t convert to DNG. There is no upside but there is a downside.

    Firstly, why bother? You have the raw files at hand – are you so limited for storage space that you need a slightly smaller file?

    Next, be aware that the best image sharpener around, viz. Dxo Optics Pro does not process converted DNG files. As I found to my cost, after erasing the orginal raw files! It does process some DNGs OOC e.g. Samsung DNGs from my old GX10 camera but that’s it.

    Wish I knew this before I converted and erased the orginal raw files (DNGS are supposed to be the same as the orginal file only smaller, so why would you keep the original raw files once you have converted?)

    • Hey James!

      Thanks for sharing your experience with DxO and DNGs. As I mentioned in the article a few reasons why we like the DNG format are the smaller files size (adds up over hundreds of thousands of images), the integration of xmp data (no sidecar files), and the embedded file verification is a nice archival feature.

      That said I can see how frustrating it must be to not be able to open the DNG file using DxO, especially if it offers superior sharpening. It’s been a while since I’ve used DxO and I hadn’t realized they dropped support for the DNG format. I’m interested to find out more about why support was dropped. Obviously if third party software producers like DxO are dropping support for DNG that’s not great news – as it does limit the number of editors you could possibly use on your files.

      Thanks again for bringing this up!

      • Hey James,

        I was thinking about the problem you brought up yesterday. Another thing I suppose you could try is exporting your DNGs as TIFF files. I don’t think you’ll lose any quality in the conversion, and then you should be able to open the TIFF files in DxO.

  15. At the end of the article you mention that there may be some issues with early DNG. What is gonna guarantee that today’s DNG won’t have issues with compatibility in the future?

    I will hold off for a while until all this gets sorted out. May be till Nikon support DNG on their cameras.

    The way I see it, Nikon should be around for long while more. And I know adobe will always support new cameras as long as Nikon is around.

    If something goes wrong with Nikon and they stop support to their RAW files its pretty sure to say that they will announce it or somebody will reported. At that moment the latest software to that date will definitely support your files, giving you a chance to change the file format.

    I’m really hoping for a standard format. But for now I will just keep an eye on the development of this. I read there still some issues with DNG which is no good for a format that is supposed to standardize everything

  16. James Behnke says:

    I’m a hobbyist and “serious family photographer” who started converting all of my Panasonic LX-5-generated RAW files into .dng in order to avoid the need to keep two libraries; one of RAW files for editing, and one of JPEGS for distribution and storage in a universally accepted format.

    I’ve revisited the whole .dng question when I (like one of the previous posters here) discovered that Corel Aftershot could not read my .dng files. That freaked me out a bit, and I’m annoyed that I can’t try Aftershot unless I want much of my recent library to be inaccessible and un-editable.

    I’ll probably stick with .dng, however, since I’m starting to recall how much of a pain it was to effectively manage and update things like keywords in what for me was essentially two separate libraries (one for RAW originals and one for the “published”, more universally compatible JPEG versions); one of the reasons that I use “professional” level editing software is for the superior organization capabilities that they afford, and I like the fact that (to the best of my knowledge) metadata like keywords can be written directly into .dng and JPEG files as opposed to “sidecar” files which can be lost or won’t be able to be read by other archiving programs.

  17. Thanks for the good advice – having to convert my 5D mk III files to DNG’s to use in Lightroom 2.7

  18. I guess I’m a little confused as I am new to this whole process. If you are converting raw files to dng is their a need to conver the dng to jpeg? Or does the dng act like a jpeg in that it can be uploaded online, etc.

    Thanks,

    Sandra